"If all that is known is that one of the children is a girl, only one possibility out of 4 is ruled out, and the answer is 2/3." Well, that's the case when you

"If all that is known is that one of the children is a girl, only one possibility out of 4 is ruled out, and the answer is 2/3." Well, that's the case when you glimpse from the window. Probably I'm wrong but I don't see why there is a fix, you still don't know if you see a G in GB or in BG or in GG